The Port of Oakland's executive director retired Monday as he was becoming increasingly embroiled in a scandal in which $4,500 in public funds were used for a party at a strip club.

Omar Benjamin and Maritime Director James Kwon had been on paid administrative leave since mid-October. In a news release issued Monday night, the port announced that Benjamin had stepped down effective immediately.

Port officials had initially been investigating Kwon, who had submitted receipts for a 2008 gathering at Treasures, an upscale strip club in Houston.

A search of port financial records by KTVU-TV also found that Kwon had also expensed $476 in haircuts, $1,000 in wine, bills from massage parlors, golf outings and a $350 pair of Ecco golf shoes. Benjamin also had apparently attended the gathering - and the port had redacted his name from public records act requests for the receipts.

Benjamin insisted he didn't remember being at the club, according to a source close to the investigation.

Kwon is contradicting his boss, saying Benjamin not only was there but told him to pick up the tab, a source has told The Chronicle.

Acting Executive Director Deborah Ale Flint will continue to direct day-to-day operations at the port, the fifth-largest container port in the nation.